Noggin, what camera do you have? If you still have the K-x, then manual focusing is you best bet. If you want to increase the success rate, then shoot using wide angles - that way you can still have a somewhat large aperture and get away with it - subject distance still matters of cause.
If you have a camera that supports setting the AF-S Mode to shutter release priority such as with K-5 or K-30, then use it - My K-30 is slow in night club type of lighting but I've found that using this setting, my success rate increases even though I do not wait for a full AF lock - it's very hard to get a lock when disco lights and people are moving fast around in such low lighting conditions
When I'm shooting wider at such low light conditions then I pre-focus manually and just fire away.